57 lines
1.2 KiB
C
57 lines
1.2 KiB
C
/*
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* Copyright (C) 1995 Advanced RISC Machines Limited. All rights reserved.
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*
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* This software may be freely used, copied, modified, and distributed
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* provided that the above copyright notice is preserved in all copies of the
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* software.
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*/
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/*
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* bytesex.c - Code to support byte-sex independence
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* Copyright: (C) 1991, Advanced RISC Machines Ltd., Cambridge, England.
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*/
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/*
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* RCS $Revision$
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* Checkin $Date$
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*/
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#include "bytesex.h"
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static int reversing_bytes = 0;
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void bytesex_reverse(yes_or_no)
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int yes_or_no;
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{ reversing_bytes = yes_or_no;
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}
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int bytesex_reversing()
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{
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return reversing_bytes;
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}
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int32 bytesex_hostval(v)
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int32 v;
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{ /* Return v with the same endian-ness as the host */
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/* This mess generates better ARM code than the more obvious mess */
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/* and may eventually peephole to optimal code... */
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if (reversing_bytes)
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{ unsigned32 t;
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/* t = v ^ (v ror 16) */
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t = v ^ ((v << 16) | (((unsigned32)v) >> 16));
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t &= ~0xff0000;
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/* v = v ror 8 */
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v = (v << 24) | (((unsigned32)v) >> 8);
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v = v ^ (t >> 8);
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}
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return v;
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}
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int32 bytesex_hostval_16(v)
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int32 v;
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{
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if (reversing_bytes) {
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v = ((v >> 8) & 0xff) | ((v << 8) & 0xff00);
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}
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return v;
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}
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